Blanca Margarita Ovelar de Duarte (born 2 September 1957) is a Paraguayan teacher and politician, currently serving as senator since 2013.

She was the Colorado Party's nominee for president in the April 2008 presidential election, in which she was defeated.

Initial results showed Ovelar narrowly defeating her rival for the nomination, former Vice President Luis Castiglioni, in the party's primary, held in December 2007;[1] however, the result was disputed, leading to a recount.

[3] Opposition candidate Fernando Lugo won the election, held on 20 April 2008, thereby ousting the Colorado Party after 61 years of continuous rule.

Ovelar conceded the race to Lugo at about 9 PM local time on election night.